The use of devices for tissue approximation and fastening is well known in the art. For example during an open abdominal interventional procedure, an incision is made through the abdominal wall to gain access to the peritoneal cavity. When the surgeon has corrected the abdominal defect, the peritoneum, abdominal muscles, fascial layers and skin must be approximated and fastened to complete the closure of the abdominal cavity. During various interventional procedures a surgical opening created in the stomach must be approximated and fastened closed to allow for the healing process to complete and to prevent stomach contents from entering the peritoneal cavity. In each case the success of the repair and ultimate healing process is highly dependent on the technique and skill of the surgeon. The process of approximating the individual layers of tissue and fastening them securely is tedious and time consuming.
Tissue approximation and fastening is well known throughout history. Suturing materials have been commonly used to aid approximation of tissue for the appropriate duration of the healing process. For example, U.S. Pat. No. 2,808,055 describes a device for surgical stitching that provides an integrated suture dispenser and feeding mechanism to enhance the surgeon's ability to apply sutures quickly and effectively. U.S. Pat. No. 4,165,747 describes methods of both approximating and fastening tissue as it is being held. Further exemplary prior art is disclosed in U.S. Pat. No. 5,565,004, U.S. Pat. No. 5,643,295 and U.S. Pat. No. 5,972,021. The disadvantages and limitations of the methods used in these devices include relatively large skin incisions and resultant scars from providing the surgeon access to the abdominal cavity. Extended time under anesthesia due to the time consuming nature of suturing the wound closed, and lengthy recovery times for patients who undergo these invasive procedures resulting in high costs. These are significant drawbacks for this type of intervention.
Advances in devices for minimally invasive interventions led to combining functionality of approximating and fastening tissues simultaneously. Exemplary prior art is disclosed in U.S. Pat. No. 5,332,142, U.S. Pat. No. 5,485,952, U.S. Pat. No. 5,662,258, U.S. Pat. No. 5,700,275 and U.S. Pat. No. 6,986,451.
These devices greatly reduced the dependence on the surgeons suturing technique by replacing the suture with surgical staples, furthermore, the mechanically fired staples greatly reduced the time necessary to approximate and fasten tissue thereby shortening the time a patient was kept under anesthesia. Additionally the use of these devices through small incisions in the skin reduced the time required for the patient to recover from surgery. However these devices are complicated to manufacture, expensive and typically require the tissue being fastened must also be transected. Additionally the approximation possible with these types of devices is limited by the size of the aperture of the open jaws of the instrument, often being less than the outside diameter of the instrument shaft itself. Another disadvantage of these devices occurs when the tissue to be fastened does not completely fill the stapler jaws; staples not in contact with tissue fall loosely into the patient's abdomen. These are significant disadvantages for this type of device.
While laparoscopic stapling devices have in many cases improved the speed of interventional procedures and reduced the dependence on an individual's technique to guarantee consistent outcomes, many interventional procedures still require the flexibility offered to the surgeon of needle and thread. Devices like the Autosuture Endo Stitch™ as described in U.S. Pat. No. 5,480,406, provides a device to facilitate suturing laparoscopically. While tedious, time consuming, and technique sensitive, laparoscopic suturing is a method used for fastening tissues to this day. Minimally invasive interventional procedures that use suture in spite of the many disadvantages noted, represent an opportunity for device innovation and improvement when, as in the present invention, these disadvantages can be overcome.
More recently, sophisticated endoscopic devices like U.S. Pat. Application No. 2004/0215216 to Gannoe discloses a tissue approximation and fixation device. The device is used to approximate two folds of soft tissue to form a pleat to be used for gastric reduction surgery or GERD treatment procedures. In this disclosure, the device fixates portions of tissue together so that the tissue can fuse or scar over, however Gannoe specifically discusses the need to apply a clamping force that does not clamp too tightly, thus leading to complications such as pressure necrosis, or too lightly, which may result in an incomplete tissue union. Thus, inconsistent securement is a problem that requires precise application of force. The present invention, as will be shown, provides the appropriate clamping force without the need for precise adjustment of clamping force by the surgeon.
Considering the technical limitations and shortcomings associated with the various methods utilized in prior art to approximate and fasten tissue, as described above, it is apparent that surgeons and patients could benefit from a minimally invasive device that approximates tissues and delivers fasteners in a faster, safer and more consistent manner, thereby providing the surgeon with greater control and flexibility to perform new beneficial interventional procedures.